The Voice Switch Service Module (VXSM) product is supported by the MGX 8880 Media Gateway and the MGX 8850 Multiservice Switch. Refer to their respective release notes for platform and version level support guidelines.

Note To verify that you have the latest version of Cisco IOS required to support the new features included in this release, please check Cisco IOS availability status at Cisco.com.

Call Rate Performance Support

•In MGCP, the maximum CPS supported is 60 (without signaling). If signaling (M3UA/IUA/RUDP) is configured, then the maximum supported CPS is 35.

•In H.248, the maximum CPS supported is 85 (without signaling). If signaling (M3UA/IUA) is configured, then the maximum supported CPS is 35.

SNMPv3

Simple Network Management Protocol Version 3 (SNMPv3) is an standards-based protocol for network management. SNMPv3 provides secure access to devices using a combination of authentication and encryption of packets over the network. This assures that data can be collected securely from SNMP devices and that configuration messages cannot be viewed or altered.

The security features provided in SNMPv3 are:

•Message integrity—Ensuring that a packet has not been tampered with in-transit.

•Authentication—Determining that the message is from a valid source.

•Encryption—Scrambling the contents of a packet to prevent it from being seen by an unauthorized source.

V.110 Support for AAL2 Trunking Applications

VXSM supports the detection and handling of V.110 traffic used for modem and fax devices on mobile networks. This feature is used in conjunction with the AAL2 Trunking function. Upon detection of a V.110 bit pattern, VXSM provides a Clear Channel circuit for the duration of the V.110 (data) session.

The V.110 feature adds the following commands:

cnfeventmapping -v110 Configure V.110 events mapping

dspeventmapping -v110 Display V.110 events mapping

addccdprof Add clear channel data profile

cnfccdprof Configure clear channel data profile

delccdprof Delete clear channel data profile

dspccdprof Display clear channel data profile

dspccdprofs Display clear channel data profiles

Unique Virtual Gateway Domain Name for H.248

For H.248 applications, a VXSM card has the capability of being partitioned into a number of virtual media gateways (VMGs); where each VMG is a logical entity residing within a physical VXSM card. This feature permits each virtual gateway to be assigned its own unique domain name.

The Unique Virtual Gateway Domain Name feature modifies the following commands:

addh248assoc Add H.248 association

cnfh248mg Configure H.248 media gateway

dsph248assoc List configuration of H.248 Association

dsph248mg List configuration of H.248 Gateway

ptime Support for H.248

The ptime (packet period) attribute is defined in RFC 2327 as "the length of time in milliseconds represented by the media in a packet." ptime specifies the packet period for a codec, and maxptime specifies the maximum packet period.

The ptime and maxptime attributes are optional SDP attributes that can be sent down by the MGC in the local or remote descriptor SDP.

In release earlier than 5.4.00, the values of ptime and maxptime were ignored and the values configured on the platform were used.

Firmware Images

For each VXSM card type (OC-3/STM-1, T1/E1, or T3), two firmware images are available, namely, Non-CALEA and CALEA. When placing an order, the user must specify whether a Non-CALEA or CALEA image is required.

The Non-CALEA image supports three Media Gateway Control protocols, namely, H.248, MGCP, and TGCP. However, VXSM supports only one protocol at a time. The user must choose between the H.248, MGCP, and TGCP protocols when the image is first loaded from the PXM using the setrev command.

The CALEA image supports TGCP and MGCP only. The protocol must be explicitly selected when the image is loaded from the PXM using the setrev command.

VXSM supports two different codec templates; "TGW/wireline" and "Cable." The Cable template can be used only in conjunction with TGCP.

Upgrading from an Earlier VXSM Release

VXSM can be gracefully upgraded (configuration is preserved) from VXSM Release 5.2.10 or later so long as the original and the upgraded images are both either CALEA or Non-CALEA.

Note Upgrading from CALEA to Non-CALEA, or Non-CALEA to CALEA, is NOT supported.

When loading or upgrading a boot or runtime image to a VXSM card, users must observe the following caution:

Caution If an H.248 association is active with SrvChgProfile (used in service change message) as BT_TGW in 5.3.x.x release, after graceful upgrade to 5.4.00, the association will continue to use BT_TGW, but new association(s) cannot be added with SrvChgProfile as BT_TGW.

From the 5.4.00 release onward, the BT_TGW SrvChgProfile is no longer available. All new associations must be added using either etsi_tgw or CISCO_TGW.

Warning Many of the commands involved in loading or upgrading boot and runtime images can take several minutes to execute completely. If the user resets or otherwise disturbs the VXSM card during a loading or upgrading process, the card can easily be damaged even to the extent that it must be returned to the factory for repair.In particular:Do not reset VXSM or PXM cards manually or through commands such as resetcd or resetsysDo not save all MGX configurations with commands such as saveallcnfs.Do not toggle primary/secondary cards through commands such as switchredcd, delred Do not change the name of software image before or during the upgradeDo not change any configuration of active primary card during the upgradeTHE REAPPEARANCE OF THE COMMAND PROMPT AFTER A COMMAND IS ENTERED DOES NOT INDICATE THAT THE IMAGE LOAD OR UPGRADE HAS BEEN COMPLETED. After the execution of the burnboot, clrsmcnf, loadrev, or setrev commands, the user must execute either a dspcds or dsprev command periodically to verify that the state of the VXSM card being loaded or upgraded is either Active, Standby, or Failed. ONLY WHEN THE CARD IS DISPLAYED TO BE IN ONE OF THESE STATES IS IT SAFE TO GO TO THE NEXT STEP.If the upgrade procedure is interrupted for reasons outside the control of the user (for example, a power outage), see "Interrupted Procedure Recovery" below for instructions.

Interrupted Procedure Recovery

In the event that a VXSM software upgrade procedure is interrupted (for example, power outage), and both Primary and Secondary are stuck in 'Failed-U' state, perform the following procedure

Step 1 Execute the abortrev command:

abortrev <PrimarySlot> <NewImageRevision>

Step 2 If the primary VXSM becomes "Failed/Active" (out of Failed-U/Active"), then execute the resetcd command

resetcd <PrimarySlot>

Step 3 If the secondary VXSM becomes "Failed/Active" (out of Failed-U/Active"), then execute the resetcd command:

resetcd <SecondarySlot>

Step 4 Both primary and secondary VXSM cards should now have their original SW image and original DB

Feature Clarifications

Online Diagnostics Feature as Applied to VXSM

The online diagnostics feature as implemented on the PXM45 card is supported on VXSM. When enabled, using the PXM45 cnfdiag command, this feature performs non-intrusive diagnostics tests that use four of the VXSM G711 DSP resources.

If the user executes the VXSM dspdspcodecpools command, the resulting display shows the four G711 DSP resources being used (for diagnostics) and subtracts them from the remaining available codecs (see example below).

mgx.3.VXSM.a > dspdspcodecpools

=====================================================================

DSP codec capacity usage

=====================================================================

Codec pool Current utilized Current available

capacity (#DSP chans) capacity (#DSP chans)

========== ===================== =====================

G711 family/HDLC 179 7885

G729/G726/T.38 family 0 3919

G723 family 0 2911

In this example, 175 G711 calls have been established along with four G711 resources used for diagnostics.

The online diagnostics feature does not reduce the maximum number of 8064 G711 DSP resources available for calls on the VXSM card. If the number of call requests on the VXSM is sufficiently high, the online diagnostic feature is disabled automatically and the four codecs are made available for active calls.

DSP Resources Under Mixed Codec Conditions

When the same codec is used to setup calls on the gateway the available DSP resources will be fully utilized. However when different codecs are used to setup calls the amount of utilizable DSP resources may be limited in certain cases due to resource fragmentation.

Fragmentation is said to have occurred when the available capacities on two different DSP resources have enough available capacity to support a call of a particular codec type but cannot support that codec type individually.

Consider two DSP resources whose available capacity is 1 unit each making the total available capacity 2 units. However a codec that requires 2 units cannot be supported in the system because the available capacities have been fragmented across the individual DSP resources.

The DSP allocation algorithm on VXSM does make an attempt to smooth the effects of fragmentation. Fragmentation can happen because the pattern of future calls cannot be predicted beforehand.

VXSM Management Information Base

The VXSM Management Information Base (MIB) Version 5.4 is available to users with CCO accounts who can access the MIB and VXSM software on-line at: http://www.cisco.com/kobayashi/sw-center/sw-wan.shtml

Step 1 Log on to http://www.cisco.com/kobayashi/sw-center/sw-wan.shtml

Step 2 Locate the VXSM platform (either VXSM 8880 or VXSM 8850) and click the down arrow to expand the "Select Release Level" drop down menu.

Open Caveats in Release 5.4.00.201

Symptom:Call setup or call modification failure is seen on calls that are affected by this non-fatal error. This error also results in associated PXM logs indicating a DSP Channel EXCEPTION.

Conditions: This issue was seen twice in an overnight run with a single codec of G.711. There is no permanent damage at the card level due to this error. The error only affects single calls. Subsequent calls on the same TDM endpoint will be unaffected by the previous occurrence of this error.

Workaround: None.

CSCek62859

Headline: Hung CCB conn even after gwfOOS and inservice

Symptoms: Hung CCBs.

Conditions: Configure VXSM for basic VOIP call, Send CRCX with signal request IT/rt, The call is dropped with error code 404 No bandwidth resource. On checking dspxgcpendptcons * it shows no current calls. In active ccb it shows a tone and no calls can be made on that end point. Tried to do a cnfgwoos 2 (forced) but activeCcbs still shows the same state.

Workaround: None.

CSCek65811

Headline: cnfgwis gives error message when the GW is in forced OOSstate already

Symptoms: cnfgwis command fails to bring VXSM Gateway state back to in-service.

Conditions: cnfgwis command fails after cnfgwoos command execution with error "Out of service operation is going on, wait for a while."

Workaround: VXSM card reset.

CSCek69535

Headline: hung calls in midcall codec chng when no bearer channel available

Symptoms: When near to maximum capacity call is made and codec is modified to a different codec family, few modify failures happen.

Conditions: When channel capacity required for new codec is more than the previous one and the DSP core, where the channel was allocated is full then modify doesn't happen successfully. This happens even if some channels in other DSP core are free.

Symptoms: The VXSM card in H248 call control protocol mode switches to standby in a call waiting scenario where first user reverts back to the second user after attending a waiting call from third user. The executed call flow is not supported by VXSM.

Conditions: When the first user reverts back to second user after attending a waiting call then VXSM switches to standby card.

Symptoms: Fax Modem call not working after midcall codec change from PCMU to G729a.

Conditions: No Upspeed after midcall codec change in a voice call from PCMU to G729a.

Workaround: None.

.

Open Caveats in Release 5.4.00.200

Table 4 Open Software Caveats in VXSM Release 5.4.00.200

DDTS Issue

Description

CSCek70423

Headline: Unable to add LAPD on 1 T1(Rest all 335 LAPDs are added).

Symptoms: addlapd returns error "ERR: DS0 already in use by B-Channel" while DS0 is free.

Condition: This problem happens when LAPDs are added on active card, but one LAPD in sequence is missed out to add (LAPD on DS1 1-3 is added, then LAPD for DS1 5-6 is added and 4th DS1 is free). If switchover happens at this time then LAPD on 4th DS1 will not be allowed to add and will return above error.

Symptom: When channel capacity required for new codec is more than the previous one and the dsp core, where the channel was allocated is full then modify doesn't happen successfully. This happens even if some channels in other DSP core are free.

Condition: When near to maximum capacity call is made and codec is modified to a different codec family, few modify failures happen.

Workaround: None.

CSCek65811

Headline: cnfgwis gives error message when the GW is already in forced OOSstate.

Symptom: cnfgwis command fails after cnfgwoos command execution with error "Out of service operation is going on, wait for a while."

Condition: cnfgwis command fails to bring VXSM Gateway state back to in-service.

Condition: When IUA is tested at high cps with mix traffic of voice + fax + modem at that time dsperrs are observed.

Workaround: None.

CSCek70878

Headline: VXSM mgcgwdn mismatch results in COT failure.

Symptom: VXSM COT tests fail 100% of the time, however bearer path is not impacted.

Condition: Extra processing when mgc domain name is not case-matched with what is configured in BTS emulates COT failure.

Workaround: Configure VXSM with exact gateway domain name found in /etc/hosts. Alternatively, configure dns on the VXSM with adddnsdn command.

CSCek70226

Headline: H.248:Out of resource error due to CDB leak.

Symptom: Commands rejected with "out of resources" error and same is loggin in dsplog alongwith "operation failed" errors in dsplog.

Condition: CDB are not freed in case of encode failures.

Workaround: None.

CSCek70118

Headline: VXSM H.248 returns Pending transactions.

Symptom: In H.248 Media gateway configuration VXSM replies with pending transactions to call agent commands. The pending transaction replies are followed by a final response containing error code 510 "Insufficient_resources."

Condition: This problem would be seen if two consecutive transactions are sent to media gateway for a same termination without waiting for a response for the first transaction. Both the transactions will be successful. But the third and subsequent transactions on this termination ID will get pending replies from gateway.

Workaround: Wait for reply of first transaction before sending next transaction to media gateway on the same termination ID.

Symptom: Call setup or call modification failure is seen on calls that are affected by this non-fatal error. This error also results in associated PXM logs indicating a DSP Channel EXCEPTION.

Condition: This issue was seen twice in an overnight run with a single codec of G.711. There is no permanent damage at the card level due to this error. The error only affects single calls. Subsequent calls on the same TDM endpoint will be unaffected by the previous occurrence of this error.

Workaround: There is no workaround for this problem at this time. It has not been completely ascertained whether the issue does not occur with COT disabled or with single codecs.

CSCek62859

Headline: Hung CCB conn even after gwfOOS and inservice.

Symptom:

Condition:

Workaround:

CSCek67800

Headline: H248:Restart SC should be sent on redirection before registration.

Symptom: ServiceChange with method handoff.

Condition: MgcIdToTry with new MGC address received in response to initial serviceChange with method restart.

Workaround: None. This will redirect to new MGC but only issue is an unnecessary audit procedure shall be initiated by new MGC.

Symptom: Fax fails on T.38 devices when call starts at g.729. The T.38 exchange looks OK on the SIP side, but the MGX never switches over to T.38 packets. The problem is that when an outbound T.38 call starts on g.729 codec, the PGW/MGX re-sends the T.38 INVITE and all looks OK, however no T.38 packets ever come from the MGX.

Condition: When PP Control is disabled on VXSM and Basic T.38 fax call fails when voice call starts with g.729 codec.

Obtaining Documentation, Obtaining Support, and Security Guidelines

For information on obtaining documentation, obtaining support, providing documentation feedback, security guidelines, and also recommended aliases and general Cisco documents, see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation, at:

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Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.